2x scaling is not setting 1080p, it's telling the software to draw at 2x scale. That's sharp and very well supported. True fractional scaling is not yet supported in most Linux software but I do 1.3x scaling for 1440p just by setting font scaling. Has worked fine for many years. Going to 4K from 1440p makes things easier on the software side as 2x is very well supported.
what i meant is setting the lcd display that has the native resolution at more then 1080 to 1080 resolution and comparing it to a native 1080 display would usually would not give the same results, as running the display at lower resolution (not scaling) would usually give you blur.
also fractional scaling works ok'ish in linux' but it's "fake" actually in that it uses xrandr to create a 2x resolution and show you scaling of that. and it uses more resources especialy with external monitors with different dpis.
No one ever runs displays non-natively to get any of the scaling being discussed here.
Fractional scaling works like that everywhere that I've seen. OSX does the same, and I'm not sure about Windows. The alternative would be properly scalable GUI toolkits which then creates other difficulties in mixed-DPI situations. I don't use that though. Font scaling is more than enough to get 1.3x scaling. Has been for years, and doesn't take the efficiency hit. It doesn't solve the mixed-DPI situation either though.
